In March 2018 researchers from the USA published their review of the medical scientific literature to assess whether the list of chemicals associated with unconventional oil and gas extraction (commonly referred to as fracking) had the potential to alter the normal functioning of the endocrine system. The fracking process is known to involve more than 1,000 chemicals such as solvents, surfactants, detergents, and biocides. These, plus a complex mixture of chemicals, including heavy metals, naturally-occurring radioactive chemicals, and organic compounds released from ground formations, enter the air and water. A total of 48 studies which had sampled the air near fracking sites were identified and if a chemical was mentioned in two or more studies, it was added to the list of detected chemicals. This resulted in a list of 106 different chemicals being generated, with ethane, benzene and n-pentane being the most frequently detected. A review of the medical scientific literature showed that 21 chemicals on the list had the potential to alter endocrine activity, including oestrogen and androgen activity. These chemicals included aromatics (ie benzene, toluene, ethylbenzene, and xylene), several polycyclic aromatic hydrocarbons, and mercury. It was also noted that the medical scientific literature suggested that some of the air pollutants may adversely affect reproduction, development and functioning of the central nervous system, all of which involve hormone production.
Bolden AL et al. Exploring the endocrine activity of air pollutants associated with unconventional oil and gas extraction. Environ Health. 2018 Mar 21;17(1):26.